The following case illustrates my propensity for limiting my use of what patent attorneys call the means plus function claim limitation.  There are particular uses for means plus function limitations but more often than not, they seem to be more trouble than they are worth.  I will go over some instances where I think that [...]

Clear claim language is generally the primary goal of claim drafting. In the following case, the claim recited a means plus function limitation. These types of limitations appear to be broad but are limited to the specific structure disclosed in the patent application and linked to the function stated in the means plus function limitation. The means plus function limitation in the patent at issue recited “a release means for retaining” which is confusing because it is unclear whether the function is the release function or the retain function. The Court held that the claim is limited to structure related to both the release and the retain function. Court held: no infringement based on this claim construction. The point of this case is to follow the simple means plus function format of “means” followed by a function, preferably only one function.

Means plus function language in a claim appears to be a broad form of claiming one’s invention.  However, Congress by statute has limited the breadth of these types of limitations to those embodiments disclosed in the patent application which are linked to the means plus function limitation plus their equivalents.  As a result, the means [...]